On occasion, there is an increasing interest to provide tires with a high level of handling, i.e. steering response, a high level of grip, and low fuel consumption. A common method of increasing the steering response of the tire is to use a tread rubber with high stiffness. High stiffness compounds typically have a high dynamic storage modulus. Conventional compounding techniques used to increase the dynamic storage modulus include using a high filler loading, using a filler with a high surface area, using less softener, and using styrene-butadiene polymers with a high styrene content. However, each of these conventional methods has performance tradeoffs.
For example, the above mentioned conventional techniques can increase the hysteresis of the rubber compound. Increasing the hysteresis of the rubber results in more energy lost as heat, and thus increases fuel consumption.
In addition, increasing the filler loading, using a filler with a high surface area, and lowering the softener level can have a negative effect on processing, as they all increase the time it takes to disperse the filler into the rubber.
Therefore, a need remains to improve the dynamic modulus of a rubber compound without significantly impacting compound hysteresis or compound processing.